静止无功补偿装置中的全数字频率自适应锁相技术

当电网不平衡和电压畸变的情况下,传统的基于dq同步坐标变换的三相同步锁相环（SRF-PLL）,存在无法准确锁定电压相位及频率的不足,不能很好满足静止无功补偿装置（SVC）的应用要求。基于目前存在的难题,提出一种易于工程实现的全数字频率自适应锁相技术,利用频率自适应相序检测器的正负序完全分离性能及其滤波特性,准确锁定电压正序基波频率和相位;给出此锁相技术在SVC主控装置中的数字实现方案,搭建基于主控装置控制算法源程序的SVC控制系统仿真模型。根据某炼钢企业电弧炉系统实际运行参数,对提出的锁相环性能进行仿真研究,PSCAD/EMTDC仿真结果表明,在电网不平衡和电压畸变时该锁相环可以准确锁定相位频率,且锁相性能不受系统频率偏差和波动的影响。

Application of digital frequency self-adaptive phase-locked loop technique in SVC system

The performance of traditional SRF-PLL can＇t meet the request of SVC control system under the circumstances of power grid unbalance and voltage waveform distortion.A new digital frequency self-adaptive PLL technique was proposed using frequency self-adaptive phase sequence detector （FAPSD）in this paper.It can separate the positive and negative component of voltage vector completely,and lock the voltage phase and frequency accurately.The digital implementation scheme of the new PLL used in the SVC main control unit （MCU）was introduced and one kind of SVC control system practical simulation model based on the interface of C and PSCAD/EMTDC was also shown in this paper.The simulation results verified that the good performance and frequency adaptation of the new PLL technique under the conditions of power grid unbalance and voltage waveform distortion.